Movable body drive system, pattern formation apparatus, exposure apparatus and exposure method, and device manufacturing method

ABSTRACT

A stage device is equipped with a first scale which is placed with a Y-axis direction serving as its longitudinal direction and in which a first grating whose periodic direction is in an X-axis direction is formed and a second scale which is placed with the X-axis direction serving as its longitudinal direction and in which a second grating whose periodic direction is orthogonal to the periodic direction of the first grating is formed, the first scale and the second scale being placed on a plane which a wafer stage faces. Further, on the upper surface of the wafer stage, a plurality of X heads placed at different positions in the X-axis direction and a plurality of Y heads placed at different positions in the Y-axis direction are arranged. An encoder system that has these heads measures positional information of the stage within an XY plane, based on an output of the X head facing the first scale and an output of the Y head facing the second scale.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Division of application Ser. No. 12/343,862 filed Dec. 24,2008, which is a non-provisional application claims the benefit ofProvisional Application No. 61/006,814, filed on Jan. 31, 2008 whichclaims priority to Japanese Patent Application No. 2007-340706, filed onDec. 28, 2007. The prior applications, including the specifications,drawings and abstract are incorporated herein by reference in theirentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to movable body drive systems, patternformation apparatuses, exposure apparatuses and exposure methods, anddevice manufacturing methods, and more particularly to a movable bodydrive system that measures the position of a movable body using anencoder system and drives the movable body substantially along apredetermined plane, a pattern formation apparatus equipped with themovable body drive system, an exposure apparatus equipped with themovable body drive system and the exposure method using the movable bodydrive system, and a device manufacturing method using the exposureapparatus or the exposure method.

2. Description of the Background Art

Conventionally, in a lithography process for manufacturing microdevices(electron devices) such as semiconductor devices and liquid crystaldisplay devices, an exposure apparatus such as a projection exposureapparatus by a step-and-repeat method (a so-called stepper) or aprojection exposure apparatus by a step-and-scan method (a so-calledscanning stepper (which is also called a scanner) is mainly used.

In this type of exposure apparatus, in general, position measurement ofa stage that holds a wafer, for example, was performed using a laserinterferometer. However, a level of required performance has becomehigher due to finer patterns accompanying higher integration ofsemiconductor devices. For example, a permissible value of a totaloverlay error becomes an order of several nm, and according to thispermissible value, a permissible value of a position control error ofthe stage becomes less than or equal to a subnano order. Accordingly,short-term variation of measurement values caused by air fluctuationsthat is generated due to temperature variation and/or temperaturegradient of an atmosphere in a beam path of the laser interferometercannot be ignored any more.

Therefore, recently, an encoder having a high resolution that is hardlyaffected by air fluctuations compared with the interferometer has beengathering attention, and an exposure apparatus that uses the encoder forposition measurement of a wafer stage or the like is proposed (e.g.refer to U.S. Patent Application Publication No. 2006/0227309, and thelike). In the case of an exposure apparatus described in the U.S. patentapplication Publication described above, a grid plate is used, which islocated above a substrate table and covers a wide range of an areaincluding an entire area of a movement range of the substrate table.

However, since it is difficult to manufacture the grid plate with alarge area and high precision as is disclosed in the U.S. patentapplication Publication described above, a plurality of grid platesneeded to be placed side by side. Fighter, to use the grid plate havinga large area as is disclosed in the U.S. patent application Publicationdescribed above has drawbacks in terms of layout and accuracy, and alsois almost unrealistic especially in terms of cost.

SUMMARY OF THE INVENTION

The present invention has been made in view of the circumstancesdescribed above, and according to a first aspect of the presentinvention, there is provided a first movable body drive system thatdrives a movable body substantially along a predetermined plane, thesystem comprising: a first scale which is placed, with a first directionserving as its longitudinal direction, on a first plane that faces themovable body and is parallel to the predetermined plane, and in which afirst grating whose periodic direction is in the first direction or in asecond direction perpendicular to the first direction is formed; asecond scale which is placed, with the second direction serving as itslongitudinal direction, on the first plane, and in which a secondgrating whose periodic direction is orthogonal to the periodic directionof the first grating is formed; a measurement system which has a firsthead group including a plurality of first heads that are placed atdifferent positions in the second direction on a second plane of themovable body substantially parallel to the predetermined plane and havetheir measurement directions in the periodic direction of the firstgrating, and a second head group including a plurality of second headsthat are placed at different positions in the first direction on thesecond plane of the movable body and have their measurement directionsin the periodic direction of the second grating, and which computespositional information of the movable body in at least directions of twodegrees of freedom within the predetermine plane including the first andsecond directions based on an output of the first head that faces thefirst scale and an output of the second head that faces the secondscale; and a drive system that drives the movable body along thepredetermined plane based on the positional information that has beencomputed by the measurement system.

With this system, based on the output of the first head that faces thefirst scale and the output of the second head that faces the secondscale, the measurement system computes positional information of themovable body in at least directions of two degrees of freedom within thepredetermined plane including the first and second directions, and basedon the positional information that has been computed by the measurementsystem, the drive system drives the movable body along the predeterminedplane. Accordingly, the movable body can be driven along thepredetermined plane with high precision, based on the measurement valuesof the measurement system in the entire area of a movement range of themovable body, without placing scales (gratings) corresponding to theentire area of the movement range of the movable body.

According to a second aspect of the present invention, there is provideda second movable body drive system that drives a movable bodysubstantially along a predetermined plane, the system comprising: ascale which is placed, with a first direction serving as itslongitudinal direction, on a first plane that faces the movable body andis parallel to the predetermined plane, and in which a two-dimensionalgrating whose periodic directions are in the first direction and in asecond direction perpendicular to the first direction is formed; ameasurement system which has a plurality of two-dimensional heads thatare placed at different positions in the second direction on a secondplane of the movable body substantially parallel to the predeterminedplane and have their measurement directions in the first and seconddirections, and which computes positional information of the movablebody in at least directions of two degrees of freedom within thepredetermine plane including the first and second directions based on anoutput of the two-dimensional head that faces the scale; and a drivesystem that drives the movable body along the predetermined plane basedon the positional information that has been computed by the measurementsystem.

With this system, based on the output of the two-dimensional head thatfaces the scale, the measurement system computes positional informationof the movable body in at least directions of two degrees of freedomwithin the predetermine plane including the first and second directions,and based on the positional information that has been computed by themeasurement system, the drive system drives the movable body along thepredetermined plane. Accordingly, the movable body can be driven alongthe predetermined plane with high precision, based on the measurementvalues of the measurement system in the entire area of a movement rangeof the movable body, without placing scales (gratings) corresponding tothe entire area of the movement range of the movable body.

According to a third aspect of the present invention, there is provideda pattern formation apparatus that forms a pattern on an object, theapparatus comprising: a patterning device that generates a pattern onthe object; and one of the first and second movable body drive systemsof the present invention, whereby a movable body, on which the object ismounted, is driven by the movable body drive system, for patternformation to the object.

With this apparatus, by the patterning device generating a pattern on anobject on the movable body that is driven with high precision by one ofthe first and second movable body drive systems of the presentinvention, it becomes possible to form the pattern on the object withhigh precision.

According to a fourth aspect of the present invention, there is provideda first exposure apparatus that forms a pattern on an object withirradiation of an energy beam, the apparatus comprising: a patterningdevice that irradiates the object with the energy beam; and one of thefirst and second movable body drive systems of the present invention,whereby a movable body, on which the object is mounted, is driven by themovable body drive system, for relative movement of the energy beam andthe object.

With this apparatus, for relative movement of an energy beam that isirradiated from the patterning device to an object and the object, themovable body on which the object is mounted is driven with highprecision by one of the first and second movable body drive systems ofthe present invention. Accordingly, the pattern can be formed on theobject with high precision by scanning exposure.

According to a fifth aspect of the present invention, there is provideda second exposure apparatus that exposes an object with an energy beam,the apparatus comprising: a movable body that can move along apredetermined plane, while holding the object; a scale that is placedsubstantially parallel to the predetermined plane, with a firstdirection serving as its longitudinal direction; and an encoder systemthat has a plurality of heads which are arranged on the movable body andwhose positions are different in a second direction orthogonal to thefirst direction within the predetermined plane, and measures positionalinformation of the movable body at least during exposure of the object,using at least one of the plurality of heads that faces the scale.

With this apparatus, a plurality of heads of the encoder system arearranged on the movable body, and positional information of the movablebody is measured by at least one of the plurality of heads that facesthe scale, which is placed substantially parallel to the predeterminedplane with the first direction serving as its longitudinal direction.

According to a sixth aspect of the present invention, there is provideda first device manufacturing method, comprising: exposing an objectusing one of the first and second exposure apparatuses of the presentinvention; and developing the exposed object.

According to a seventh aspect of the present invention, there isprovided a first exposure method of exposing an object with an energybeam, the method comprising: holding the object with a movable body; anddriving the movable body by one of the first and second movable bodydrive systems of the present invention and exposing the object with theenergy beam.

With this method, since the movable body that holds an object is drivenwith high precision by one of the first and second movable body drivesystems of the present invention, favorable exposure can be performed tothe object.

According to an eighth aspect of the present invention, there isprovided a second exposure method of exposing an object held by amovable body that moves substantially along a predetermined plane, withan energy beam, wherein a first scale and a second scale are placed on afirst plane that faces the movable body and is parallel to thepredetermined plane, the first scale being placed with a first directionserving as its longitudinal direction and having a first grating formedtherein whose periodic direction is in the first direction or in asecond direction perpendicular to the first direction, and the secondscale being placed with the second direction serving as its longitudinaldirection, and having a second grating formed therein whose periodicdirection is orthogonal to the periodic direction of the first grating,the method comprises: a measurement process of computing positionalinformation of the movable body in at least directions of two degrees offreedom within the predetermine plane including the first and seconddirections, based on an output of a first head that faces the firstscale and an output of a second head that faces the second scale, fromamong a first head group including a plurality of the first heads thatare placed at different positions in the second direction on a secondplane of the movable body substantially parallel to the predeterminedplane and have their measurement directions in the periodic direction ofthe first grating, and a second head group including a plurality of thesecond heads that are placed at different positions in the firstdirection on the second plane of the movable body and have theirmeasurement directions in the periodic direction of the second grating;and a drive process of driving the movable body along the predeterminedplane based on the positional information that has been computed in themeasurement process.

With this method, based on the output of the first head that faces thefirst scale and the output of the second head that faces the secondscale, positional information of the movable body in at least directionsof two degrees of freedom within the predetermined plane including thefirst and second directions is computed, and based on the computedpositional information, the movable body is driven along thepredetermined plane. Accordingly, the movable body can be driven alongthe predetermined plane with high precision based on the measurementvalues of the measurement system in the entire area of a movement rangeof the movable body, without placing scales (gratings) corresponding tothe entire area of the movement range of the movable body, and hencehigh-precision exposure can be performed to an object held on themovable body.

According to a ninth aspect of the present invention, there is provideda third exposure method of exposing an object held by a movable bodythat moves substantially along a predetermined plane, with an energybeam, wherein a scale, in which a two-dimensional grating whose periodicdirections are in a first direction and in a second directionperpendicular to the first direction is formed, is placed with the firstdirection serving as its longitudinal direction, on a first plane thatfaces the movable body and is parallel to the predetermined plane; themethod comprises: a measurement process of computing positionalinformation of the movable body in at least directions of two degrees offreedom within the predetermine plane including the first and seconddirections based on an output of a two-dimensional head that faces thescale, from among a plurality of the two-dimensional heads that areplaced at different positions in the second direction on a second planeof the movable body substantially parallel to the predetermined planeand have their measurement directions in the first and seconddirections; and a drive process of driving the movable body along thepredetermined plane based on the positional information that has beencomputed in the measurement process.

With this method, based on the output of the two-dimensional head thatfaces the scale, positional information of the movable body in at leastdirections of two degrees of freedom within the predetermined planeincluding the first and second directions is computed, and based on thecomputed positional information, the movable body is driven along thepredetermined plane. Accordingly, the movable body can be driven alongthe predetermined plane with high precision based on the measurementvalues of the measurement system in the entire area of a movement rangeof the movable body, without placing scales (gratings) corresponding tothe entire area of the movement range of the movable body, and hencehigh-precision exposure can be performed to an object held on themovable body.

According to a tenth aspect of the present invention, there is provideda fourth exposure method of exposing an object held by a movable bodythat can move along a predetermined plane, with an energy beam, themethod comprising: measuring positional information of the movable bodyat least during exposure of the object, with at least one head of aplurality of heads that faces a scale that is placed substantiallyparallel to the predetermined plane with a first direction serving asits longitudinal direction, by using an encoder system that has theplurality of heads which are arranged on the movable body and whosepositions are different in a second direction orthogonal to the firstdirection within the predetermined plane.

With this method, by using the encoder system having a plurality ofheads whose positions are different in the second direction that arearranged on the movable body, positional information of the movable bodyis measured by at least one of the plurality of heads that faces thescale that is placed substantially parallel to the predetermined planewith the first direction serving as its longitudinal direction, at leastduring exposure of an object.

According to an eleventh aspect of the present invention, there isprovided a second device manufacturing method, comprising: exposing anobject using any one of the second, third and fourth exposure methods ofthe present invention; and developing the exposed object.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings;

FIG. 1 is a view schematically showing a configuration of an exposureapparatus related to an embodiment;

FIG. 2 is a view enlarging and showing components in the vicinity of astage device shown in FIG. 1;

FIG. 3 is a plan view showing a wafer stage together with encoders andinterferometers that measure positional information of the wafer stage;

FIG. 4 is a block diagram showing a control system related to stagecontrol of the exposure apparatus of the embodiment with a part of thecontrol system omitted;

FIG. 5A is a view showing a state where the wafer stage is located at aposition at which a portion near the center of a wafer is positioneddirectly under a projection unit PU, and FIG. 5B is a view showing astate where the wafer stage is located at a position at which a midportion between the center and the circumference of the wafer ispositioned directly under the projection unit;

FIG. 6A is a view showing a state where the wafer stage is located at aposition at which a portion near a +Y side edge of the wafer ispositioned directly under projection unit PU, and FIG. 6B is a viewshowing a state where the wafer stage is located at a position at whicha portion near an edge of the wafer, which is angled at 45 degrees withrespect to the X-axis and the Y-axis when viewed from the center of thewafer, is positioned directly under projection unit PU;

FIG. 7 is a view showing a state where the wafer stage is located at aposition at which a portion near a +X side edge of the wafer ispositioned directly under projection unit PU;

FIG. 8 is a view showing an encoder system for a wafer stage related toanother embodiment; and

FIG. 9 is a view showing an encoder system for a wafer stage related toyet another embodiment.

DESCRIPTION OF THE EMBODIMENTS

An embodiment of the present invention is described below, withreference to FIGS. 1 to 7.

FIG. 1 shows a schematic configuration of an exposure apparatus 100related to the embodiment. Exposure apparatus 100 is a reductionprojection exposure apparatus by a step-and-scan method, which is aso-called scanner. As is described later, a projection optical system PLis provided in this embodiment, and in the description below, theexplanation is given assuming that a direction parallel to an opticalaxis AX of projection optical system PL is a Z-axis direction, adirection in which a reticle and a wafer are relatively scanned within aplane orthogonal to the Z-axis direction is a Y-axis direction, and adirection that is orthogonal to a Z-axis and a Y-axis is an X-axisdirection, and rotation (inclination) directions about an X-axis, theY-axis and the Z-axis are θx, θy and θz directions, respectively.

Exposure apparatus 100 is equipped with an illumination system 10, areticle stage RST that holds a reticle R, a projection unit PU, a waferstage device 12 including a wafer stage WST on which wafer W is mounted,and their control system, and the like.

As is disclosed in, for example, U.S. Patent Application Publication No.2003/0025890 and the lie, illumination system 10 includes: a lightsource; and an illumination optical system that has an illuminanceuniformity optical system containing an optical integrator and the like,and a reticle blind and the like (none of which are shown). Illuminationsystem 10 illuminates a slit-shaped illumination area IAR, which isdefined by the reticle blind (a masking system), on reticle R with anillumination light (exposure light) IL with substantially uniformilluminance. In this case, as illumination light IL, an ArF excimerlaser light (wavelength: 193 nm) is used, as an example.

On reticle stage RST, reticle R having a pattern surface (a lowersurface in FIG. 1) on which a circuit pattern and the like are formed isfixed by, for example, vacuum suction. Reticle stage RST is finelydrivable within the XY plane and also drivable at a designated scanningspeed in a scanning direction (which is the Y-axis direction being alateral direction of the page surface of FIG. 1), with a reticle stagedrive system 11 including, for example, a linear motor or the like.

Positional information (including rotational information in the θzdirection) of reticle stage RST within the XY plane (a movement plane)is constantly detected at a resolution of, for example, around 0.25 nmwith a reticle laser interferometer (hereinafter, referred to as a“reticle interferometer”) 16 shown in FIG. 1 via a movable mirror 15 (inactuality, a Y movable mirror (or a retroreflector) having a reflectionsurface orthogonal to the Y-axis direction and an X movable mirrorhaving a reflection surface orthogonal to the X-axis direction arearranged), with a fixed mirror 14 (in actuality, each of an X fixedmirror and a Y fixed mirror) as a reference, which is fixed to the sidesurface of a barrel 40 that constitutes projection unit PU.

Projection unit PU is held by a part (a barrel platform) of a body (notshown) via a flange FLG below reticle stage RST in FIG. 1. Projectionunit PU includes barrel 40 which has a cylindrical shape and has flangeFLG arranged in the vicinity of a lower end of the outer peripherythereof, and projection optical system PL which is held by barrel 40 andis composed of a plurality of optical elements. As projection opticalsystem PL, for example, a dioptric system that is composed of aplurality of optical elements (lens elements) disposed along opticalaxis AX parallel to the Z-axis direction is used. Projection opticalsystem PL is, for example, both-side telecentric and has a predeterminedprojection magnification (e.g. one-quarter, or one-fifth). Therefore,when illumination area IAR is illuminated by illumination light IL fromillumination system 10, illumination light IL having passed throughreticle R whose pattern surface is placed substantially coincident witha first plane (an object plane) of projection optical system PL forms areduced image of a circuit pattern (a reduced image of a part of acircuit pattern) of the reticle within illumination area IAR on an area(an exposure area) that is conjugate to illumination area IAR describedpreviously on wafer W, which is placed on a second plane (an imageplane) side of projection optical system PL and whose surface is coatedwith a resist (a sensitive agent), via projection optical system PL.Then, by moving reticle R relative to illumination area IAR(illumination light IL) in the scanning direction (the Y-axis direction)and also moving wafer W relative to the exposure area (illuminationlight IL) in the scanning direction (the Y-axis direction) bysynchronous drive of reticle stage RST and wafer stage WST, scanningexposure of one shot area (divided area) on wafer W is performed, and apattern of reticle R is transferred to the shot area. More specifically,in this embodiment, a pattern is generated on wafer W by illuminationsystem 10, reticle R and projection optical system PL, and the patternis formed on wafer W by exposure of a sensitive layer (a resist layer)on wafer W with illumination light IL.

Wafer stage device 12 is equipped with a stage base 71 that is supportedalmost horizontally with a plurality (e.g. 3 or 4) of vibrationisolation mechanisms (omitted in the drawings) placed on a base plate BSinstalled on a floor surface F, wafer stage WST that is placed abovestage base 71, a wafer stage drive system 27 (not shown in FIG. 1, referto FIG. 4) that drives wafer stage WST, and the like.

Stage base 71 is made up of a member having a tabular outer shape, andits upper surface is finished so as to have a very high level offlatness degree, and serves as a guide plane used when wafer stage WSTmoves. Inside stage base 71, a coil unit is housed, which includes aplurality of coils placed in a matrix shape with the XY two dimensionaldirections serving as a row direction and a column direction.

As shown in FIG. 2, wafer stage WST has a stage main body 30 and a wafertable WTB which is the upper section of stage main body 30, and on thebottom portion of stage main body 30, a magnetic unit 31 having aplurality of magnets, which constitutes a magnetic levitation typeplanar motor together with the coil unit, is arranged. In theembodiment, the coil unit has not only an X-axis direction drive coiland a Y-axis direction drive coil, but also a Z-axis direction drivecoil, and the coil unit and the magnetic unit described above constitutea moving magnet type planar motor (a two dimensional linear actuator) bya electromagnetic drive method (Lorenz force drive method), which driveswafer stage WST in directions of six degrees of freedom which are theX-axis direction, the Y-axis direction, the Z-axis direction, the θxdirection, the θy direction, and the θz direction. Wafer stage drivesystem 27 is configured including the planar motor described above. Inthe embodiment, the magnitude and direction of electric current suppliedto each coil constituting the coil unit are controlled by maincontroller 20.

Incidentally, wafer stage WST can also employ, for example, a structurethat is equipped with a stage main body that is driven within the XYplane by a linear motor, a planar motor, or the like, and a wafer tablethat is finely driven in at least directions of three degrees of freedomwhich are the Z-axis direction, the θx direction, and the θy directionon the stage main body by a voice coil motor or the like. In such acase, a planar motor by the Lorenz electromagnetic drive which isdisclosed in, for example, U.S. Pat. No. 5,196,745 and the like can alsobe used. Incidentally, the planar motor is not limited to the Lorenzelectromagnetic drive method, but a planar motor by a variable magneticresistance drive method can also be used.

On wafer table WTB, wafer W is mounted via a wafer holder (not shown),and fixed by, for example, vacuum suction (for electrostatic suction) orthe like.

Further, a configuration is employed in which positional information ofwafer stage WST within the XY plane can be measured by an encoder system50 (refer to FIG. 4) including scale members 46B, 46C, 46D and the like,and a wafer laser interferometer system (hereinafter, shortly referredto as an “interferometer system”) 18, respectively. A configuration andthe like of encoder system 50 and interferometer system 18 for waferstage WST are described in detail below. Incidentally, the scale membercan also be called a grid plate, a grating member, a reference memberand the like.

As shown in a plan view of FIG. 3, on the upper surface of wafer tableWTB (wafer stage WST), a plurality (ten each, in this case) of X heads(hereinafter, shortly referred to as heads, as needed) 66 ₁ to 66 ₁₀ andY heads (hereinafter, shortly referred to as heads, as needed) 64 ₁ to64 ₁₀ are arranged so as to enclose wafer W. To be more specific, at the+Y side end and the −Y side end of the wafer table WTB upper surface, Xheads 66 ₁, 66 ₂, . . . , 66 ₅ and 66 ₆, 66 ₇, . . . , 66 ₁₀ are placedat a predetermined distance along the X-axis direction. And, at the +Xside end and the −X side end of wafer table WTB upper surface, Y heads64 ₁, 64 ₂, . . . , 64 ₅ and 64 ₆, 64 ₇, . . . , 64 ₁₀ are placed at apredetermined distance along the Y-axis direction. As each of Y heads 64₁ to 64 ₁₀ and X heads 66 ₁ to 66 ₁₀, a head having a configurationsimilar to the head (the encoder) that is disclosed in, for example,U.S. Pat. No. 7,238,931 or the pamphlet of International Publication No.2007/083758 (the corresponding U.S. Patent Application Publication No.2007/0288121) or the like is used. Incidentally, in the descriptionbelow, Y heads 64 ₁ to 64 ₁₀ and X heads 66 ₁ to 66 ₁₀ are alsodescribed as Y heads 64 and X heads 66, respectively.

Meanwhile, as can be seen when viewing FIGS. 1 and 3 together, fourscale members 46A to 46D are placed in a state of enclosing theperiphery of the lowermost end of projection unit PU from four sides. Inactuality, scale members 46A to 46D are fixed to the barrel platform ina suspended state via, for example, a support member, although omittedin FIG. 1 to avoid intricacy of the drawing.

Scale members 46A and 46C are placed on the −X side and the +X side ofprojection unit PU with the X-axis direction serving as theirlongitudinal directions and are placed symmetrically with respect tooptical axis AX of projection optical system PL. Further, scale members46B and 46D are placed on the +Y side and the −Y side of projection unitPU with the Y-axis direction serving their longitudinal directions andare placed symmetrically with respect to optical axis AX of projectionoptical system PL.

Scale members 46A to 46D are made of the same material (e.g. a ceramic,a glass having a low thermal expansion, or the like), and on the surfaceof each scale member (the lower surface in FIG. 1, i.e., the surface onthe −Z side), a same reflective diffraction gratings having the periodicdirection in a direction perpendicular to the longitudinal direction isformed. This diffraction grating is made by being engraved with a pitchbetween 138 nm to 4 μm, e.g., with a pitch of 1 μm. Incidentally, inFIG. 3, the pitch of the grating is shown remarkably wider compared withthe actual pitch, for the sake of convenience for illustration. Further,on the surfaces (the grating surfaces of scale members 46A to 46D, acover member (e.g. a glass plate or the like), which is substantiallytransparent with respect to a measurement beam from the head describedabove, can be arranged.

Since scale members 46A and 46C have the diffraction gratings whoseperiodic direction is in the Y-axis direction, they are used forposition measurement of wafer stage WST in the Y-axis direction. And,scale members 46B and 46D have the diffraction gratings whose periodicdirection is in the X-axis direction, they are used for positionmeasurement of wafer stage WST in the X-axis direction.

In the embodiment, X heads 66 ₁, 66 ₂, . . . , 66 ₅, and 66 ₆, 66 ₇, . .. , 66 ₁₀ are placed on wafer table WTB at a distance with whichadjacent two X heads 66 can face a corresponding scale member(diffraction grating) simultaneously, or more specifically, at adistance that is less than or equal to around a length of thediffraction grating in a direction (an arrangement direction of thediffraction grating) that is orthogonal to the longitudinal direction ofscale members 46B and 46D.

Similarly, Y heads 64 ₁ to 64 ₅ and 64 ₆ to 64 ₁₀ are placed on wafertable WTB at a distance with which adjacent two Y heads 64 can face acorresponding scale member (diffraction grating) simultaneously, or morespecifically, at a distance that is less than or equal to around alength of the diffraction grating in a direction (an arrangementdirection of the diffraction grating) that is orthogonal to thelongitudinal direction of scale members 46A and 46C.

Each of Y heads 64 ₁ to 64 ₅ and 64 ₆ to 64 ₁₀ faces any one of scalemembers 46C and 46A and constitutes a multiple-lens, or to be moreprecise, five-lens Y linear encoder that measures the Y-position ofwafer stage WST. Further, each of X heads X heads 66 ₁, 66 ₂, . . . , 66₅, and 66 ₆, 66 ₇, . . . , 66 ₁₀ faces any one of scale members 46B and46D and constitutes a multiple-lens, or to be more precise, five-lens Xlinear encoder that measures the X-position of wafer stage WST.

In the movement range of wafer stage WST on exposure where wafer W islocated below projection optical system PL (projection unit PU), Y heads64 _(i) (i=any one of 1 to 5) and 64 _(j) (j=i+5) respectively facescale members 46C and 46A, and also X heads 66 _(p) (p=any one of 1 to5) and 66 _(q) (q=p+5) respectively face scale members 46B and 46D. Morespecifically, the measurement values of four encoders in total, whichare a pair of Y linear encoders 50C and 50A (refer to FIG. 4)constituted by Y heads 64 _(i) and 64 _(j) that face scale members 46Cand 46A respectively, and a pair of X linear encoders 50B and 50D (referto FIG. 4) constituted by X heads 66 _(p) and 66 _(g) that face scalemembers 46B and 46D respectively, are supplied to main controller 20.Encoder system 50 shown in FIG. 4 is configured including a pair of Ylinear encoders 50C and 50A and a pair of X linear encoders 50B and 50D.

Further, as shown in FIG. 2, interferometer system 18 constantly detectspositional information of wafer stage WST, for example, at a resolutionof around 0.25 nm, by irradiating a reflection surface formed on the endsurface of wafer table WTB and a movable mirror 43 fixed to stage mainbody 30 with a measurement beam. At least a part of interferometersystem 18 (e.g. an optical unit excluding a light source) is fixed to abarrel platform in a suspended state.

As shown in FIG. 3, on wafer stage WST, a reflection surface 17Y that isorthogonal to the Y-axis direction serving as a scanning direction and areflection surface 17X that is orthogonal to the X-axis directionserving as a non-scanning direction are actually formed, but thesereflection surfaces are shown as a reflection surface 17 as arepresentative in FIG. 1.

As shown in FIG. 3, interferometer system 18 includes fiveinterferometers, which are a wafer Y interferometer 18Y, two wafer Xinterferometers 18X₁ and 18X₂, and a pair of Z interferometers 18Z₁ and18Z₂. As each of these interferometers 18Y, 18X₁, 18X₂, 18Z₁ and 18Z₂, aMichaelson-type heterodyne laser interferometer that uses two-frequencylaser making use of the Zeeman effect is used. Of these interferometers,as wafer Y interferometer 18Y, a multiaxial interferometer is used,which has a plurality of measurement axes including two measurement axesthat are symmetric with respect to an axis (a reference axis) parallelto the Y-axis that passes through optical axis AX (the center of theexposure area conjugate to illumination area IAR described earlier) ofprojection optical system PL and a detection center of an alignmentsystem ALG (to be described later), as shown in FIG. 3. Incidentally,wafer Y interferometer 18Y is further described later on.

Wafer X interferometer 18X₁ irradiates reflection surface 17X with ameasurement beam along a measurement axis that passes through an axis (areference axis) parallel to the X-axis that passes though optical axisAX (the center of the exposure area described earlier) of projectionoptical system PL. Wafer X interferometer 18X₁ measures a displacementof reflection surface 17X, with a reflection surface of the X fixedmirror that is fixed to the side surface of barrel 40 of projection unitPU serving as a reference, as positional information of wafer stage WSTin the X-axis direction.

Wafer X interferometer 18X₂ irradiates reflection surface 17X with ameasurement beam along a measurement axis in the X-axis direction thatpasses through the detection center of alignment system ALG, andmeasures a displacement of reflection surface 17X, with a reflectionsurface of the fixed mirror that is fixed to the side surface ofalignment system ALG serving as a reference, as positional informationof wafer stage WST in the X-axis direction.

Further, as shown in FIGS. 1 and 2, movable mirror 43 with the X-axisdirection serving as its longitudinal direction is attached to the sidesurface on the +Y side of stage main body 30 via a kinematic supportmechanism (not shown).

A pair of Z interferometers 18Z₁ and 18Z₂ that irradiate movable mirror43 with measurement beams are placed facing movable mirror 43 (refer toFIG. 3). To be specific, as can be seen when viewing FIGS. 2 and 3together, movable mirror 43 is made up of a member whose length in theX-axis direction is longer than that of reflection surface 17Y (wafertable WTB) and which has a hexagonal sectional shape like a combinationof a rectangular and an isosceles trapezoid. Mirror-polishing is appliedto the surface on the +Y side of movable mirror 43, and three reflectionsurfaces as shown in FIG. 2 are formed.

As can be seen from FIG. 3, Z interferometers 18Z₁ and 18Z₂ are placedon one side and the other side of Y interferometer 18Y in the X-axisdirection spaced apart at substantially the same distance from Yinterferometer 18Y. And, Z interferometers 18Z₁ and 18Z₂ are actuallyplaced at a position slightly lower than Y interferometer 18Y,respectively.

From each of Z interferometers 18Z₁ and 18Z₂, as shown in FIGS. 2 and 3,a measurement beam B1 in the Y-axis direction is irradiated toward theupper side reflection surface (inclined surface) of movable mirror 43and a measurement beam B2 in the Y-axis direction is irradiated towardthe lower side reflection surface (inclined surface) of movable mirror43. In this embodiment, a fixed mirror 47A having a reflection surfaceorthogonal to measurement beam B1 that has been reflected off the upperside reflection surface, and a fixed mirror 47B having a reflectionsurface orthogonal to measurement beam B2 that has been reflected offthe lower side reflection surface are arranged extending in the X-axisdirection, respectively, at a position a predetermined distance apart tothe +Y direction from projection unit PU in a state of not interferingwith measurement beams B1 and B2. Fixed mirrors 47A and 47B aresupported by, for example, a same support body (not shown) arranged onthe barrel platform that supports projection unit PU.

Measurement beams B1 and B2 in the Y-axis direction from each of Zinterferometers 18Z₁ and 18Z₂ respectively are irradiated toward movablemirror 43, and these measurement beams B1 and B2 are incident on theupper and lower reflection surfaces of movable mirror 43, respectively,at a predetermined incident angle, and then are reflected off each ofthe reflection surfaces respectively and are incident perpendicularly tothe reflection surfaces of fixed mirrors 47A and 47B. Then, measurementbeams B1 and B2 reflected off the reflection surfaces of fixed mirrors47A and 47B inversely pass through the same optical path as the opticalpath at the time of incidence and return to Z interferometers 18Z₁ and18Z₂.

As shown in FIG. 3, Y interferometer 18Y irradiates reflection surface17Y with measurement beams B4 ₁ and B4 ₂ along measurement axes in theY-axis direction that is a same distance apart on the −X side and +Xside from a straight line (reference axis) parallel to the Y-axis thatpasses through the projection center (optical axis AX, refer to FIG. 1)of projection optical system PL, and receives a reflection light of eachof measurement beams B4 ₁ and B4 ₂, thereby detecting positionalinformation of wafer stage WST in the Y—axis direction at irradiationpoints of measurement beams B4 ₁ and B4 ₂, with a reflection surface ofthe Y fixed mirror fixed to the side surface of barrel 40 of projectionunit PU serving as a reference. Incidentally, in FIG. 2, measurementbeams B4 ₁ and B4 ₂ are representatively shown as a beam B4.

Further, Y interferometer 18Y irradiates a measurement beam B3 along ameasurement axis in the Y-axis direction that is a predetermineddistance spaced apart from measurement beams B4 ₁ and B4 ₂ in the Z-axisdirection, toward a center reflection surface parallel to the XZ planeof movable mirror 43, and receives measurement beam B3 reflected off thecenter reflection surface, thereby detecting the position of the centerreflection surface of movable mirror 43 (i.e. wafer stage WST) in theY-axis direction.

Based on the average value of the measurement values of the measurementaxes corresponding to measurement beams B4 ₁ and B4 ₂ of Yinterferometer 18Y, main controller 20 computes the Y-position ofreflection surface 17Y, that is, the Y-position of wafer table WTB(wafer stage WST), or more specifically, a displacement ΔYo in theY-axis direction. Further, based on the Y-position of reflection surface17Y and the center reflection surface of movable mirror 43, maincontroller 20 computes a displacement (pitching amount) ΔXo of waferstage WST in the rotational direction (θx direction) about the X-axisdirection.

Further, based on the measurement results of Z interferometers 18Z₁ and18Z₂, main controller 20 can computes displacements ΔZo, ΔYo, Δθz andΔθy of wafer stage WST in the Z-axis direction, the Y-axis direction,the θz direction and the θy direction, by the method that is disclosedin, for example, the pamphlet of International Publication No.2007/083758 (the corresponding U.S. Patent Application Publication No.2007/0288121) and the like.

Incidentally, in FIG. 1, X interferometers 18X₁ and 18X₂, Yinterferometer 18Y, and Z interferometers 18Z₁ and 18Z₂ arerepresentatively shown as interferometer system 18, and the X fixedmirror for X-axis direction position measurement and the Y fixed mirrorfor Y-axis direction position measurement are representatively shown asa fixed mirror 57. Further, alignment system ALG and the fixed mirrorfixed thereto are omitted in FIG. 1.

In this embodiment, wafer X interferometer 18X₁ and Y interferometer 18Yare used for calibration of an encoder system that is used during anexposure operation of wafers, and wafer X interferometers 18X₂ and waferY interferometer 18Y are used during mark detection by alignment systemALG. Incidentally, in this embodiment, instead of forming reflectionsurfaces 17X and 17Y on the end surfaces of wafer table WTB, a movablemirror (planar mirror) can be fixed to the end of wafer stage WST.

Further, on wafer stage WST, a fiducial mark plate (not shown) is fixedin a state where its surface has the same height as wafer W. On thesurface of the fiducial mark plate, at least one pair of first fiducialmarks for reticle alignment and a second fiducial mark for baselinemeasurement of alignment system ALG, which has a known positionalrelation with the first fiducial marks, and the like are formed.

Exposure apparatus 100 of this embodiment is further equipped with apair of reticle alignment systems 13A and 13B (not shown in FIG. 1,refer to FIG. 4) that are placed a predetermined distance apart in theX-axis direction above reticle stage RST. As reticle alignment systems13A and 13B, a TTR (Through The Reticle) alignment system is used thatuses a light with an exposure wavelength for simultaneously observing apair of the first fiducial marks on wafer stage WST and a pair ofreticle marks on a reticle corresponding to the first fiducial marks viaprojection optical system PL. The detailed configuration of the reticlealignment system is disclosed in, for example, U.S. Pat. No. 5,646,413and the like. Incidentally, as the reticle alignment system, forexample, an aerial image measuring system whose light-receiving surfacehaving a slit opening is placed on wafer stage WST can be used insteador together. In this case, the first fiducial marks described earlier donot have to be arranged.

Similarly, although omitted in FIG. 1, exposure apparatus 100 is furtherequipped with a multipoint focal position detecting system by an obliqueincident method that is composed of an irradiation system 42 a and aphotodetection system 42 b (refer to FIG. 4), which is similar to theone disclosed in, for example, U.S. Pat. No. 5,448,332 and the like.

Further, in exposure apparatus 100, in the vicinity of projection unitPU, alignment system ALG described earlier (not shown in FIG. 1, referto FIG. 3) is arranged. As alignment system ALG, for example, an FIA(Field Image Alignment) system by an image processing method is used.Alignment system ALG supplies positional information of marks with anindex center serving as a reference to main controller 20. Based on theinformation that has been supplied and on the measurement values of themeasurement axes corresponding to measurement beams B4 ₁ and B4 ₂ ofwafer Y interferometer 18Y and the measurement values of wafer Xinterferometer 18X₂ of interferometer system 18, main controller 20measures positional information of the mark subject to detection, ormore specifically, the second fiducial mark on the fiducial mark plateor the alignment mark on the wafer on a coordinate system (an alignmentcoordinate system) that is defined by the measurement axes of wafer Yinterferometer 18Y and wafer X interferometer 18X₂.

FIG. 4 shows a control system related to stage control of exposureapparatus of this embodiment in a block diagram, with the system beingpartially omitted. The control system shown in FIG. 4 includes aso-called microcomputer (or workstation), which is composed of a CPU(Central Processing Unit), an ROM (Read Only Memory), an RAM (RandomAccess Memory), and the like, and is mainly configured by maincontroller 20 that performs overall control of the entire apparatus.

In exposure apparatus 100 having the configuration as described above,during a wafer alignment operation that is performed by a known EGA(Enhanced Global Alignment), which is disclosed in, for example, U.S.Pat. No. 4,780,617, and the like, as is described above, based on themeasurement values of wafer Y interferometer 18Y and wafer Xinterferometer 18X₂ of interferometer system 18, the position of waferstage WST within the XY plane is controlled by main controller 20, andduring operations other than the wafer alignment operation, for example,during an exposure operation, based on the measurement values ofencoders 50A to 50D, the position of wafer stage WST is controlled bymain controller 20.

Accordingly, during a period after the wafer alignment operation iscompleted until the exposure is started, a switching operation of aposition measurement system needs to be performed, in which the positionmeasurement system used for position measurement of the wafer stagewithin the XY plane is switched from wafer Y interferometer 18Y andwafer X interferometer 18X₂ to encoders 50A to 50D. This switchingoperation of the position measurement system is performed roughly in thefollowing procedure.

After the wafer alignment is completed, main controller 20 drives waferstage WST in a predetermined direction, for example, in the +Ydirection, based on the measurement values of interferometers 18Y, 18X₂,18Z₁ and 18Z₂.

Then, when wafer stage WST reaches a position where the measurement beamfrom interferometer 18X₂ and the measurement beam from interferometer18X₁ are simultaneously irradiated to reflection surface 17X, maincontroller 20 adjusts the attitude of wafer stage WST based on themeasurement values of interferometer system 18 (interferometers 18Y,18X₂, 18Z₁ and 18Z₂) so that a θz rotation (yawing) error (and a θxrotation (pitching) error and a θy rotation (rolling) error) is reducedto zero, and then pre-sets the measurement value of interferometer 18X₁to a same value as the measurement value of interferometer 18X₂ at thepoint in time.

After the pre-setting, wafer stage WST is stopped at the position for apredetermined period of time until the influence of short-term variationdue to air fluctuations (temperature fluctuations of air) of themeasurement value of each axis of interferometers 18X₁ and 18Y isreduced to an ignorable level by averaging effect, and the averagedvalue of the measurement values of interferometer 18X₁ acquired duringthe stop time (the averaged value during the stop time) is carried overas the measurement value of X linear encoders 50B and 50D, and also theaveraged value of the averaged values (the averaged values during thestop time) of the respective measurement values of a plurality of axesof interferometer 18Y acquired during the stop time is carried over asthe measurement value of Y linear encoders 50A and 50C. Accordingly, thepre-setting of X linear encoders 50B and 50D and Y linear encoders 50Aand 50C, or more specifically, the switching operation of the positionmeasuring system is completed. After that, main controller 20 controlsthe position of wafer stage WST based on the measurement values ofencoders 50A to 50D.

In exposure apparatus 100 of this embodiment, similar to theconventional scanning stepper, a series of operations such as reticlealignment (which includes relating the reticle coordinate system to thewafer coordinate system) and baseline measurement of alignment systemALG is performed using the fiducial mark plate on wafer stage WST,alignment system ALG and the like. Position control of reticle stage RSTand wafer stage WST during the series of operations is performed basedon the measurement values of reticle interferometer 16 andinterferometer system 18.

Next, main controller 20 performs wafer exchange on wafer stage WST(performs wafer loading, in the case where there is no wafer on waferstage WST) using a wafer loader (not shown), and wafer alignment (e.g.EGA or the like) with respect to the wafer using alignment system ALG.With this wafer alignment, an arrangement coordinate of a plurality ofshot areas on the wafer on the alignment coordinate system describedpreviously is obtained.

After that, the switching of the position measuring system describedearlier is performed, and while controlling the position of wafer stageWST based on the baseline measured in advance and the measurement valuesof encoders 50A to 50D, and controlling the position of reticle stageRST based on the measurement values of reticle interferometer 16described previously, main controller 20 performs exposure bystep-and-scan method in the procedure similar to that of theconventional scanning stepper, thereby a pattern of reticle R istransferred onto a plurality of shot areas, respectively, on the wafer.

FIG. 5A shows a state where wafer stage WST is located at a positionwhere the vicinity of the center of wafer W is directly under projectionunit PU, and FIG. 5B shows a state where wafer stage WST is located at aposition where the vicinity of an area in between the center and theperiphery of wafer W is directly under projection unit PU. Further, FIG.6A shows a state where wafer stage WST is located at a position wherethe vicinity of the +Y side edge of wafer W is directly under projectionunit PU, and FIG. 6B shows a state where wafer stage WST is located at aposition where the vicinity of the edge, which is in a direction angledat 45-degrees with respect to the X-axis and the Y-axis when viewed fromthe center of wafer W, of wafer W is directly under projection unit PU.Further, FIG. 7 shows a state where wafer stage WST is located at aposition where the vicinity of the +X side edge of wafer W is directlyunder projection unit PU. When viewing FIGS. 5A to 7, it can be seenthat in any one of these drawings, at least one head (in thisembodiment, one head or two heads), which belongs to each group of fourgroups consisting of Y heads 64 ₁ to 64 ₅, Y heads 64 ₆ to 64 ₁₀, Xheads 66 ₁ to 66 ₅, and X heads 66 ₆ to 66 ₁₀ on wafer table WTB faces acorresponding scale member. As can be seen when comprehensivelyconsidering this fact, and the symmetric arrangement of scale members46A to 46D in the vertical direction and the horizontal direction withoptical axis AX of projection optical system PL as the center, and thesymmetric arrangement of Y heads 64 ₁ to 64 ₁₀ and X heads 66 ₁ to 66 ₁₀in the X-axis direction and the Y-axis direction with respect to thecenter of wafer stages WST, in exposure apparatus 100, even if waferstage WST is located at any position within a movement range of waferstage WST during exposure, one each of Y heads 64 ₁ to 64 ₅ and Y heads64 ₆ to 64 ₁₀, and X heads 66 ₁ to 66 ₅ and X heads 66 ₆ to 66 ₁₀ facesthe corresponding moving scale, and measurement of the X-position andthe Y-position of wafer stage WST with four encoders 50A to 50D can bealmost simultaneously performed at all times.

In other words, the length of the arrangement area of each of the fourhead groups, 64 ₁ to 64 ₅, 64 ₆ to 64 ₁₀, 66 ₁ to 66 ₅ and 66 ₆ to 66 ₁₀(e.g., in the case of head group 64 ₁ to 64 ₅, the distance to coverhead 64 ₁ and 64 ₅) is set longer than a size (diameter) of wafer W soas to cover the entire area of the movement stroke (movement range) ofwafer stage WST when scanning exposure is performed to at least theentire surface of wafer W (in this embodiment, so that any of four headgroups 64 ₁ to 64 ₅, 64 ₆ to 64 ₁₀, 66 ₁ to 66 ₅ and 66 ₆ to 66 ₁₀(measurement beams) does not move off from the corresponding scalemember (diffraction grating), or more specifically, so that any of thefour head groups does not become incapable of performing measurement, atleast during scanning exposure and a period of acceleration/decelerationand synchronous stabilization of wafer stage WST before and after thescanning exposure, for all the shot areas).

Further, similarly, the length of each of four scale members 46A to 46Din each longitudinal direction (which corresponds to the width of thediffraction grating) is set longer than or equal to around the movementstroke so as to cover the entire area of the movement stroke of waferstage WST when scanning exposure is performed to at least the entiresurface of wafer W (i.e., so as to prevent four head groups 64 ₁ to 64₅, 64 ₆ to 64 ₁₀, 66 ₁ to 66 ₅ and 66 ₆ to 66 ₁₀ (measurement beams)from moving off from the corresponding scale members (diffractiongratings), or more specifically, so as to prevent the four head groupsfrom becoming incapable of performing measurement, at least during theexposure operation for wafer W).

As is described in detailed above, according to exposure apparatus 100of the present embodiment, encoder system 50 computes positionalinformation of wafer stage WST in directions of three degrees of freedomwithin the XY plane based on the output of a pair of Y heads 64 thatrespectively face scale members 46A and 46C and the output of a pair ofX heads 66 that respectively face scale members 46B and 46D, and inresponse to instructions of main controller 20, wafer stage drive system27 drives wafer stage WST along the XY plane based on the positionalinformation computed by encoder system 50. Accordingly, it becomespossible to drive wafer stage WST with high precision along the XY planebased on the measurement values of encoder system 50, in the entire areaof the movement range of wafer stage WST, without placing the scales(gratings) so as to correspond to the entire area of the movement rangeof wafer stage WST.

Further, according to exposure apparatus 100 of the present embodiment,during scanning exposure to each shot area on wafer W, main controller20 can drive reticle R (reticle stage RST) and wafer W (wafer stage WST)in the scanning direction (the Y-axis direction) with high precisionbased on the measurement values of reticle interferometer 16 andencoders 50A and 50C (and 50B and 50D), and can also drive wafer W(wafer stage WST) in the non-scanning direction (the X-axis direction)with high precision, which also makes it possible to perform thehigh-precision positioning (alignment) of reticle R (reticle stage RST)and wafer W (wafer stage WST) in the non-scanning direction.Accordingly, the pattern of reticle R can be formed with high precisionon a plurality of shot areas on wafer W.

Incidentally, for each encoder used in this embodiment, various methodssuch as the diffraction interference method described above, or aso-called pickup method can be used, and a scan encoder or the like,which is disclosed in, for example, U.S. Pat. No. 6,639,686 and thelike, can be used.

Next, another embodiment of the present invention is described based onFIG. 8. In an exposure apparatus of this embodiment, since only anencoder system for a wafer stage is different from that in thepreviously described embodiment, the encoder system is described below.Incidentally, only the configuration of the encoder system is thedifference from FIG. 3, and therefore in the description below, the samereference signs are applied to the constituents having the same orequivalent operations or functions as/to those shown in FIG. 3, and theexplanation thereof is omitted. Further, interferometer system 18 isomitted in FIG. 8.

As shown in FIG. 8, scale members 46A′ and 46B′ each having an elongatedrectangular plate shape are placed on the −X side and the +Y side of thelowermost end of projection unit PU. These scale members 46A′ and 46B′are actually fixed to the barrel platform in a suspended state via asupport member.

Scale member 46A′ is placed on the −X side of projection unit PU withthe X-axis direction serving as its longitudinal direction, in a statewhere an extended line of a center line related to a directionperpendicular to the longitudinal direction (a center line extending inthe longitudinal direction) is orthogonal to the optical axis ofprojection optical system PL. On the surface (the −Z side surface) ofscale member 46A′, a reflective type diffraction grating with apredetermined pitch, for example, with a 1 μm pitch whose periodicdirection is in the X-axis direction is formed in the similar manner tothe manner previously described.

Further, scale member 46B′ is placed on the +Y side of projection unitPU with the Y-axis direction serving as its longitudinal direction, in astate where an extended line of a center line related to a directionperpendicular to the longitudinal direction (a center line extending inthe longitudinal direction) is orthogonal to the extended line of thecenter axis of scale member 46A′ in the longitudinal direction at theoptical axis of projection optical system PL. On the surface (the −Zside surface) of scale member 46B′, a reflective type diffractiongrating with a predetermined pitch, for example, with a 1 μm pitch whoseperiodic direction is in the Y-axis direction is formed in the similarmanner to the manner previously described. In this case, the width ofscale member 46A′ in a direction perpendicular to the longitudinaldirection (the width of the diffraction grating) is almost the same asthat of scale member 46A described earlier, and the width of scalemember 46B′ (the width of the diffraction grating) is about twice thewidth of scale member 46A′ (the width of the diffraction grating).

Meanwhile, on the upper surface of wafer table WTB, X heads 66 ₁, 66 ₂,. . . , 66 ₅ are placed respectively at positions where Y heads 64 ₆, 64₇, . . . , 64 ₁₀ were placed in the embodiment described earlier.Further, on the upper surface of wafer table WTB, Y heads 64 ₁, 64 ₂, .. . , 64 ₅ are placed respectively at positions where X heads 66 ₁, 66₂, . . . , 66 ₅ were placed in the embodiment described earlier.

In this embodiment, in the movement range of wafer stage WST duringexposure where wafer W is located below projection optical system PL, atleast two adjacent Y heads 64 _(i) and 64 _(i+1) (i=any one of 1 to 4)simultaneously face scale member 46B′, and also at least one X head 66_(p) (p=any one of 1 to 5) faces scale member 46A′. More specifically,the measurement values of a total of three encoders, which are two Ylinear encoders constituted by Y heads 64 _(i) and 64 _(i+1) facingscale member 46B′, and an X linear encoder constituted by X head 66 _(p)facing scale member 46A′, are supplied to main controller 20. Based onpositional information in the X-axis and Y-axis directions androtational information in the θz direction of wafer stage WST, which arecomputed based on the measurement values of these three encoders, maincontroller 20 performs position control of wafer stage WST via waferstage drive system 27. Accordingly, two-dimensional drive of wafer stageWST with high precision becomes possible in the same manner as in theabove-described embodiment.

Incidentally, in FIG. 8, the length of the arrangement area of the twohead groups, 64 ₁ to 64 ₅ and 66 ₁ to 66 ₅ (e.g., in the case of headgroup 64 ₁ to 64 ₅, the distance to cover head 64 ₁ and 64 ₅) is setlonger than a size (diameter) of wafer W so as to cover the entire areaof the movement stroke (movement range) of wafer stage WST at leastduring the exposure operation of wafer W (in other words, so as toprevent each of the head groups (measurement beams) from moving off fromthe corresponding scale member (diffraction grating), or morespecifically, so as to prevent each of the head groups from becomingincapable of performing measurement, during scanning exposure of all theshot areas). Further, in the encoder system shown in FIG. 8, the length(corresponding to the formation range of the diffraction grating) ofscale member 46A′ or scale member 46B′ in the longitudinal direction isset longer than or equal to around the movement stroke so as to coverthe entire area of the movement stroke (movement range) of wafer stageWST at least during the exposure operation of wafer W (in other words,so as to prevent each of the head groups (measurement beams) from movingoff from the corresponding scale (diffraction grating), or morespecifically, so as to prevent each of the head groups from becomingincapable of performing measurement, during scanning exposure of all theshot areas).

Next, yet another embodiment of the present invention is described basedon FIG. 9. In an exposure apparatus of this embodiment, since only anencoder system for a wafer stage is different from that in thepreviously described embodiments, the encoder system is described below.Incidentally, only the configuration of the encoder system is thedifference from FIG. 3, and therefore in the description below, the samereference signs are applied to the constituents having the same orequivalent operations or functions as/to those shown in FIG. 3, and theexplanation thereof is omitted.

In FIG. 9, a scale member 46B″ having an elongated rectangular plateshape is placed on the +Y side of the lowermost end of projection unitPU. Scale member 46B″ has the same size (length and width) as scalemember 46′ described previously. On the surface (the side surface) ofscale member 46B″, however, a reflective type two-dimensionaldiffraction grating that is composed of a grating with a predeterminedpitch, for example, a 1 μm pitch having a periodic direction in theY-axis direction and a grating with a predetermined pitch, for example,a 1 μm pitch having a periodic direction in the X-axis direction isformed.

Further, on the upper surface of wafer table WTB, five two-dimensionalheads (2D heads) 68 ₁ to 68 ₅ are placed at a predetermined distance inthe X-axis direction, in the same arrangement as with head groups 64 ₁to 64 ₅ shown in FIG. 8 described previously. Each two dimensional headcan be configured, for example, including a pair of X diffractiongratings and a pair of Y diffraction gratings (fixed scales) that emitmeasurement beams in the +Z direction and converge diffracted lights ofa predetermined order of the measurement beams from the two-dimensionaldiffraction grating; an index scale made up of a transmissive typetwo-dimensional diffraction grating, which makes the diffracted lightsthat have been converged respectively at the pair of X diffractiongratings and the pair of Y diffraction gratings interfere; a detectorthat detects the lights that have interfered at the index scale. Morespecifically, a two-dimensional encoder head by a so-called threegrating diffraction interference method can be used as 2D heads 68 ₁ to68 ₅. Incidentally, instead of the 2D heads, a one-dimensional head (Xhead) with a measurement direction in the x-axis direction and aone-dimensional head (Y head) with a measurement direction in the Y-axisdirection can be used in combination. In this case, the irradiationpositions of the measurement beams of the X head and the Y head do nothave to be at a same position. Incidentally, in the present description,a term “two-dimensional head” is used as a concept including thecombination of two one-dimensional heads like the combination of the Xhead and the Y head as described above.

In the stage device equipped with the encoder system having theconfiguration shown in FIG. 9, in the movement range of wafer stage WSTduring exposure where wafer W is located under projection optical systemPL, at least two adjacent 2D heads 68 _(i) and 68 _(i+1) (i=any one of 1to 4) simultaneously face scale member 46B″. More specifically, themeasurement values of the two two-dimensional encoders constituted by 2Dheads 68 _(i) and 68 _(i+1) that face scale member 46B″ are supplied tomain controller 20. Main controller 20 performs position control ofwafer stage WST via wafer stage drive system 27, based on positionalinformation in the X-axis and Y-axis directions and rotationalinformation in the θz direction of wafer stage WST that are computedbased on the measurement values of these two encoders. Accordingly,high-precision two-dimensional drive of wafer stage WST becomes possiblein the same manner as in the embodiments above.

Incidentally, in the cases such as where the rotational information ofwafer stage WST in the θz direction does not have to be measured, orwhere the rotational information in the θz direction measured byinterferometer system 18 is used, a configuration can be employed inwhich at least one of 2D heads 68 ₁ to 68 ₅ faces scale member 46B″. Inthis case, instead of scale member 46B″, two scale members in whichtwo-dimensional diffraction gratings are formed can be arranged. Bydoing so, the entire area of the movement range of wafer stage WST atleast during the exposure operation can be covered while keeping thesize of each scale member from increasing. In this case, the two scalemembers can be placed so that the respective longitudinal directions areorthogonal to each other or can be placed with the respectivelongitudinal directions in a same direction.

Incidentally, in each of the embodiments above, although positioncontrol of wafer stage WST is to be performed using the encoder systemdescribed earlier during the exposure operation of the wafer, positioncontrol of wafer stage WST can be performed using the encoder systemshown in the drawings such as FIGS. 3, 8, and 9 also in operations suchas an alignment operation (including at least a mark detection operationwith alignment system ALG) and/or an exchange operation of wafers. Inthis case, the switching operation of the position measuring systemdescribed previously naturally becomes unnecessary.

In this case, in the case where the encoder system described earlier(FIGS. 3, 8 and 9) is used also during operations such as detection ofalignment marks on wafer W or the second fiducial marks of wafer stageWST using alignment system ALG, it is preferable that the arrangement(e.g. including at least one of the position and the number) of theheads and/or the arrangement of the scale members (e.g. including atleast one of the position, the number and the size) are/is set alsotaking into consideration the movement range of wafer stage WST duringthis detection operation. More specifically, also during the detectionoperation of the marks that is performed after the wafer stage is movedto the measurement position of alignment system ALG, for example, inorder to make position measurement in directions of three degrees offreedom of the X-axis, Y-axis and θz directions possible, it ispreferable that the arrangement of the heads and/or the scale members isset so that at least three heads constantly continue to face the sameand/or different scale (s) (diffraction grating (s)) correspondingthereto, or more specifically, so that the position control of the waferstage is prevented from discontinuing due to the position measurementwith the encoder system becoming impossible. In this case, as anexample, the size of the scale members in each of the embodiments can beset so that the scale members can be used both in the exposure operationand the alignment operation, or scale members to be used in thealignment operation can be arranged separately from the scale membersdescribed previously. Especially in the latter case, for example, thescale members should be arranged for alignment system ALG in thearrangement similar to the arrangement as shown in the drawings such asFIGS. 3, 8 and 9. Or, by using at least one of a plurality of scalemembers used in the exposure operation and at least one scale memberarranged separately, position measurement of wafer stage WST can beperformed with the encoder system also in the alignment operation or thelike.

Incidentally, during detection of the first fiducial marks of waferstage WST with the reticle alignment system described earlier, and/orduring detection of projected images of marks of reticle R or referencemarks of reticle stage RST with the aerial image measuring systemdescribed earlier, the position measurement of wafer stage WST with theinterferometer system described previously can be performed, but it ispreferable that the position measurement of wafer stage WST is performedwith the encoder system including the scale members of each of theabove-described embodiments.

Further, in the case where the encoder system described earlier (FIGS.3, 8 and 9) is used when wafer stage WST is located at the exchangeposition of wafers (including at least one of the loading position andthe unloading position), it is preferable that the arrangement and thelike of the heads and/or the scales are set, in the similar manner tothe manner described earlier, taking into consideration the movementrange of the wafer stage in the wafer exchange operation as well. Morespecifically, it is preferable that the arrangement of the heads and/orthe scale members is set so that the position control of the wafer stageis prevented from discontinuing due to the position measurement with theencoder system becoming impossible, also at the wafer exchange position.Further, this can be said for the case where the encoder systemdescribed earlier (FIGS. 3, 8 and 9) is used during movement of waferstage WST between the exchange position of wafers and the exposureposition where a reticle pattern is transferred via projection opticalsystem PL or the measurement position where mark detection withalignment system ALG is performed, and/or between the measurementposition of alignment system ALG and the exposure position.

Moreover, as is disclosed in, for example, U.S. Pat. No. 6,262,796 andthe like, also in the case of an exposure apparatus by atwin-wafer-stage method that can execute an exposure operation and ameasurement operation (e.g. mark detection with an alignment system andthe like) almost in parallel using two wafer stages, position control ofeach wafer stage can be performed using the encoder system describedearlier (FIGS. 3, 8 and 9) in which heads are arranged at each waferstage similarly to each of the embodiments above. In this case, not onlyduring the exposure operation but also during another operation, forexample, during the measurement operation, position measurement of eachwafer stage can be performed with the encoder system described earlierby appropriately setting the arrangement of the heads and/or the scalemembers in the similar manner to the manner described previously. Forexample, by appropriately setting the arrangement of the heads, positioncontrol of each wafer stage can be performed using the scale members ofeach of the embodiments above without change, but a scale member thatcan be used during the measurement operation can also be arrangedseparately from the foregoing scale members. In this case, as anexample, four scale members that are placed in the arrangement similarto the scale members of each of the embodiments above, for example,placed in a cross shape with alignment system ALG as the center arearranged, and positional information of each wafer stage can be measuredwith these scale members and the corresponding heads during themeasurement operation described above. In the case of the exposureapparatus by a twin-wafer-stage method, for example, heads are arrangedrespectively in the arrangement similar to the previously-described case(FIGS. 3, 8 and 9) and when the exposure operation of a wafer mounted onone wafer stage is completed, the other wafer stage on which a nextwafer, to which mark detection and the like have been performed at themeasurement position, is mounted is placed at the exposure position inexchange of the one wafer stage. Further, the measurement operation thatis performed in parallel with the exposure operation is not limited tomark detection of the wafer with the alignment system, but detection ofsurface information (such as level difference information) of the wafercan also be performed instead of or in combination with the markdetection.

Incidentally, in the description above, in the case where positioncontrol of the wafer stage using the encoder system described previouslyis discontinued at the measurement point or the exchange point, orduring movement of the wafer stage from one of the exposure position,the measurement position and the exchange position to the otherposition, the position control of the wafer stage at the respectivepositions or during the movement referred to above is preferablyperformed using another measurement device (e.g. an interferometer, anencoder, or the like) that is separate from the encoder system.

Further, in each of the embodiments above, as is disclosed in, forexample, the pamphlet of International Publication No. 2005/074014 (thecorresponding U.S. Patent Application Publication No. 2007/0127006) andthe like, a measurement stage is arranged separately from the waferstage and the measurement stage is placed directly under projectionoptical system PL in exchange of the wafer stage during operations suchas the exchange operation of wafers, and the characteristics of theexposure apparatus (e.g. the image-forming characteristic (wavefrontaberration) of the projection optical system, the polarizationcharacteristic of illumination light IL, or the like) can be measured.In this case, the heads are also placed on the measurement stage andposition control of the measurement stage can be performed using thescale members described earlier. Further, during the exposure operationof a wafer mounted on the wafer stage, the measurement stage withdrawsto a predetermined position that does not interfere with the wafer stageand accordingly the measurement stage is moved between this withdrawalposition and the exposure position. Therefore, the arrangement of theheads and/or the scale members is preferably set similarly to the casedescribed earlier so as to prevent position measurement by the encodersystem from becoming, impossible and position control of the measurementstage from being discontinued also at the withdrawal position or alsoduring movement from one of the withdrawal position and the exposureposition to the other, by also taking a movement range of themeasurement stage into consideration similarly to the case of the wafersstage. Alternatively, in the case where the position control of themeasurement stage by the encoder system described earlier isdiscontinued at the withdrawal position or during the movement, theposition control of the measurement stage is preferably performed usinganother measurement device (e.g. an interferometer, an encoder or thelike) which is separate from the encoder system. Or, the positioncontrol of the measurement stage can be performed only with theinterferometer system described earlier.

Further, in each of the embodiments above, a distance between a pair ofthe scale members that are arranged extending in a same direction has tobe increased, due to, for example, a size of projection unit PU, andtherefore during scanning exposure of a specific shot area on wafer W,for example, a shot area located on the outermost circumference, acorresponding head does not face one of the pair of the scale members insome cases. As an example, when the size of projection unit PU shown inFIG. 3 is slightly increased, any corresponding X head 66 does not facescale member 46B of a pair of scale members 46B and 46D. Furthermore, ina liquid immersion type exposure apparatus in which a space betweenprojection optical system PL and a wafer is filled with a liquid (e.g.pure water or the like), which is disclosed in, for example, thepamphlet of International Publication No. 99/49504 and the like, anozzle member or the like that supplies the liquid is arranged so as toenclose projection unit PU, and therefore it becomes more difficult toplace the heads close to the exposure area described earlier ofprojection optical system PL. Accordingly, in the case of employing theencoder system shown in FIG. 3 in the liquid immersion type exposureapparatus, two pieces of positional information in each of the X-axisand Y-axis directions doe not have to be constantly measurable, but theencoder system should be configured so that two pieces of positionalinformation are measurable in one of the X-axis and Y-axis directionsand one piece of positional information is measurable in the other. Morespecifically, in the position control of the wafer stage (or themeasurement stage) with the encoder system, two pieces of positionalinformation in each of the X-axis and Y-axis directions, which are fourpieces of positional information in total, do not necessarily have to beused.

Further, in each of the embodiments above, the configuration ofinterferometer system 18 is not limited to the one shown in FIG. 3, butfor example, when the scale members are placed also at alignment systemALG (at the measurement position), interferometer system 18 does nothave to be equipped with wafer X interferometer 18X₂, or wafer Xinterferometer 18X₂ can be constituted by, for example, a multiaxialinterferometer similar to wafer Y interferometer 18Y, and rotationalinformation (e.g. yawing and rolling) of wafer stage WST can also bemeasured besides the X-position of wafer stage WST. Furthermore, in eachof the embodiments above, interferometer system 18 is to be used forcalibration of the encoder system or for position measurement of thewafer stage in operations other than the exposure operation, but this isnot to be intended to be limiting, and encoder system 50 andinterferometer system 18 can be used together in at least one of theexposure operation, the measurement operation (including the alignmentoperation), and the like. For example, in the case where encoder system50 cannot perform measurement or its measurement values are abnormal,encoder system 50 can be switched to interferometer system 18 tocontinue position control of wafer stage WST. Incidentally, in each ofthe embodiments above, interferometer system 18 does not have to bearranged, and the encoder system can only be arranged.

Further, in each of the embodiments above, the position of wafer stageWST in at least one of the X-axis and Y-axis directions is to bemeasured with encoder system 50, but this is not intended to belimiting, and position measurement in the Z-axis direction can also beperformed. For example, heads by an encoder method that can measure theposition in the Z-axis direction can be arranged on the wafer stageseparately from the heads described previously, or the heads describedpreviously can be heads that can measure the position in at least one ofthe X-axis and Y-axis directions and the position in the Z-axisdirection.

Further, in the encoder system shown in FIGS. 3 and 8, at least eitherof the X heads or Y heads are replaced with the 2D heads and the scalemember facing the 2D heads can be a scale member on which atwo-dimensional diffraction grating is formed. In this case, in theencoder system shown in FIG. 3, the number of the scale members can bedecreased from four to two at the fewest, and in the encoder systemshown in FIG. 8, by using a scale member on which a two-dimensionalgrating is formed as scale member 46B′ in particular, the width of thescale member 46B′ can be narrower.

Further, each of the embodiments above, a configuration is employed inwhich a plurality of measurement beams can constantly be irradiated toone scale member, and in the case where one measurement beam becomesabnormal, measurement can be continued by switching it to anothermeasurement beam. In this case, a plurality of measurement beams can beirradiated to the scale member from one head, or from a plurality ofdifferent heads. In the case where a plurality of measurement beams areirradiated to one scale member, the plurality of measurement beams arepreferably irradiated to different positions on the scale member.

Further, each of scale members described earlier can be configured bymaking a plurality of small scale members be integrally held on a platemember or the like. In this case, when a head that faces a connectingsection between the small scale members becomes unmeasurable or hasmeasurement abnormality, position measurement can be performedalternatively using another head that faces sections other than theconnecting section.

Further, the arrangement of the heads described in each of theembodiments above is an example, and the arrangement of the heads is notintended to be limiting.

Further, in each of the embodiments described above, the scale membersare to be fixed in a suspension state to the barrel platform via thesupport member, but the scale members can be held by another holdingmember other than the barrel platform. Further, in each of theembodiments described above, the temperature adjustment of the scalemembers can also be performed as needed.

Further, in each of the embodiments described above, since the scales(gratings) do not have to be placed corresponding to the entire area ofthe movement range of wafer stage WST, there is also the effect that theair conditioning can be performed more easily.

Incidentally, in each of the embodiments described above, the case hasbeen described where the present invention is applied to the scanningstepper, but this is not intended to be limiting, and the presentinvention can also be applied to a static exposure apparatus such as astepper. Even with the stepper, by measuring the position of a stage, onwhich an object that is subject to exposure is mounted, using anencoder, occurrence of position measurement error caused by airfluctuations can be reduced to almost zero, which is unlike the casewhere the position of the stage is measured using an interferometer, andtherefore the position of the stage can be set with high precision basedon the measurement values of the encoder, which consequently makes itpossible to transfer of a reticle pattern on the object with highprecision. Further, the present invention can also be applied to areduction projection exposure apparatus by a step-and-stitch method thatsynthesizes a shot area and a shot area.

Further, the magnification of the projection optical system in theexposure apparatus in each of the embodiments described above is notonly a reduction system, but also can be either an equal magnifyingsystem or a magnifying system, and projection optical system PL is notonly a dioptric system, but also can be either a catoptric system or acatadioptric system, and in addition, the projected image can be eitheran inverted image or an upright image.

Further, illumination light IL is not limited to the ArF excimer laserlight (wavelength: 193 nm), but can be an ultraviolet light such as aKrF excimer laser light (wavelength: 248 nm), or a vacuum ultravioletlight such as an F₂ laser light (wavelength: 157 nm). As is disclosedin, for example, U.S. Pat. No. 7,023,610, a harmonic wave, which isobtained by amplifying a single-wavelength laser beam in the infrared orvisible range emitted by a DFB semiconductor laser or fiber laser asvacuum ultraviolet light, with a fiber amplifier doped with, forexample, erbium (or both erbium and ytteribium), and by converting thewavelength into ultraviolet light using a nonlinear optical crystal, canalso be used.

Further, in each of the embodiments above, illumination light IL of theexposure apparatus is not limited to the light having a wavelength morethan or equal to 100 nm, and it is needless to say that the light havinga wavelength less than 100 nm can be used. For example, the presentinvention can also be applied to an EUV (Extreme Ultraviolet) exposureapparatus that uses an EUV light in a soft X-ray range (e.g. awavelength range from 5 to 15 nm). Besides such an apparatus, thepresent invention can also be applied to an exposure apparatus that usescharged particle beams such as an electron beam or an ion beam.

Further, in each of the embodiments above, a transmissive type mask(reticle), which is a transmissive substrate on which a predeterminedlight shielding pattern (or a phase pattern or a light attenuationpattern) is formed, is used. Instead of this reticle, however, as isdisclosed in, for example, U.S. Pat. No. 6,778,257, an electron mask(which is also called a variable shaped mask, an active mask or an imagegenerator, and includes, for example, a DMD (Digital Micromirror Device)that is a type of anon-emission type image display device (spatial lightmodulator) or the like) on which a light-transmitting pattern, areflection pattern, or an emission pattern is formed according toelectronic data of the pattern that is to be exposed can also be used.In the case of using such a variable shaped mask, a stage on which awafer, a glass plate or the like is mounted is scanned relative to thevariable shaped mask, and therefore the equivalent effect to each of theembodiments above can be obtained by measuring the position of the stagewith an encoder.

Further, as is disclosed in, for example, the pamphlet of InternationalPublication No. 2001/035168, the present invention can also be appliedto an exposure apparatus (lithography system) that forms line-and-spacepatterns on wafer W by forming interference fringes on wafer W.

Moreover, the present invention can also be applied to an exposureapparatus that synthesizes two reticle patterns on a wafer via aprojection optical system and almost simultaneously performs doubleexposure of one shot area on the wafer by one scanning exposure, as isdisclosed in, for example, U.S. Pat. No. 6,611,316.

Further, an apparatus that forms a pattern on an object is not limitedto the exposure apparatus (lithography system) described previously, andfor example, the present invention can also be applied to an apparatusthat forms a pattern on an object by an ink-jet method.

Incidentally, an object on which a pattern is to be formed (an objectsubject to exposure to which an energy beam is irradiated) in each ofthe embodiments above is not limited to a wafer, but may be anotherobject such as a glass plate, a ceramic substrate, a film member, or amask blank.

The use of the exposure apparatus is not limited to the exposureapparatus for manufacturing semiconductor devices, but the presentinvention can also be widely applied, for example, to an exposureapparatus for liquid crystal display devices that transfers a liquidcrystal display device pattern onto a rectangular glass plate, and anexposure apparatus for producing organic ELs, thin-film magnetic heads,imaging devices (such as CCDs), micromachines, DNA chips, and the like.Further, the present invention can be applied not only to an exposureapparatus for producing microdevices such as semiconductor devices, butcan also be applied to an exposure apparatus that transfers a circuitpattern onto a glass substrate or silicon wafer to produce a reticle ora mask used in a light exposure apparatus, an EUV exposure apparatus, anX-ray exposure apparatus, an electron-beam exposure apparatus, and thelike.

Incidentally, the movable body drive system of the present invention canbe applied not only to the exposure apparatus, but can also be appliedwidely to other substrate processing apparatuses (such as a laser repairapparatus, a substrate inspection apparatus and the like), or toapparatuses equipped with a movable stage such as a position settingapparatus of a sample or a wire bonding apparatus in other precisionmachines.

Incidentally, the above disclosures of all the publications, thepamphlets of the International Publications, and specifications of theU.S. patent application Publications and the U.S. patents that are citedin the description above and related to exposure apparatuses and thelike are each incorporated herein by reference.

Incidentally, semiconductor devices are manufactured through thefollowing steps: a step where the function/performance design of adevice is performed, a step where a reticle is manufactured based onthis design step; a step where a wafer is manufactured from siliconmaterials; a lithography step where a pattern formed on the mask istransferred onto an object such a wafer by the exposure apparatus ineach of the embodiments above; a development step where the exposedwafer is developed; an etching step where an exposed member of an areaother than the area where resist remains is removed by etching; a resistremoving step where the resist that is no longer necessary when theetching is completed is removed; a device assembly step (including adicing process, a bonding process, and a packaging process); aninspection step; and the like. In this case, since the exposureapparatus of each of the embodiments above is used in the lithographystep, the devices with high integration can be manufactured with goodyield.

While the above-described embodiments of the present invention are thepresently preferred embodiments thereof, those skilled in the art oflithography systems will readily recognize that numerous additions,modifications, and substitutions may be made to the above-describedembodiments without departing from the spirit and scope thereof. It isintended that all such modifications, additions, and substitutions fallwithin the scope of the present invention, which is best defined by theclaims appended below.

1. A movable body drive system that drives a movable body substantiallyalong a predetermined plane, the system comprising: a first scale whichis placed, with a first direction serving as its longitudinal direction,on a first plane that faces the movable body and is parallel to thepredetermined plane, and in which a first grating whose periodicdirection is in the first direction or in a second directionperpendicular to the first direction is formed; a second scale which isplaced, with the second direction serving as its longitudinal direction,on the first plane, and in which a second grating whose periodicdirection is orthogonal to the periodic direction of the first gratingis formed; a measurement system which has a first head group including aplurality of first heads that are placed at different positions in thesecond direction on a second plane of the movable body substantiallyparallel to the predetermined plane and have their measurementdirections in the periodic direction of the first grating, and a secondhead group including a plurality of second heads that are placed atdifferent positions in the first direction on the second plane of themovable body and have their measurement directions in the periodicdirection of the second grating, and which computes positionalinformation of the movable body in at least directions of two degrees offreedom within the predetermine plane including the first and seconddirections based on an output of the first head that faces the firstscale and an output of the second head that faces the second scale; anda drive system that drives the movable body along the predeterminedplane based on the positional information that has been computed by themeasurement system.
 2. The movable body drive system according to claim1, wherein the first scale has a width, which three of the first headscan simultaneously face, in the second direction, and the measurementsystem computes positional information of the movable body in directionsof three degrees of freedom within the predetermined plane, based onoutputs of at least two of the first heads that simultaneously face thefirst scale and an output of the second head that faces the secondscale.
 3. The movable body drive system according to claim 1, wherein apair of the first scales are placed at a predetermined distance on thefirst plane, with the first direction serving as theirs longitudinaldirections, the first head group is placed on the second plane ofmovable body in an arrangement in which at least one each of the firstheads can simultaneously face each of the pair of the first scales whenthe movable body is located in a predetermined effective area, and themeasurement system computes positional information of the movable bodyin directions of three degrees of freedom within the predeterminedplane, based on outputs of two of the first heads that simultaneouslyface the pair of the first scales respectively, and an output of thesecond head that faces the second scale.
 4. The movable body drivesystem according to claim 1, wherein a pair of the second scales areplaced at a predetermined distance on the first plane, with the seconddirection serving as their longitudinal directions, the second headgroup is placed on the second plane of the movable body in anarrangement in which at least one each of the second heads cansimultaneously face each of the pair of the second scales when themovable body is located in the effective area, and the measurementsystem computes positional information of the movable body in directionsof three degrees of freedom within the predetermined plane, based onoutputs of two of the first heads that simultaneously face the pair ofthe first scales respectively, and outputs of two of the second headsthat simultaneously face the pair of the second scales respectively. 5.The movable body drive system according to claim 1, wherein the drivesystem includes a planar motor that drives the movable body along thepredetermined plane.
 6. A pattern formation apparatus that forms apattern on an object, the apparatus comprising: a patterning device thatgenerates a pattern on the object; and the movable body drive systemaccording to claim 1, whereby a movable body, on which the object ismounted, is driven by the movable body drive system, for patternformation to the object.
 7. The pattern formation apparatus according toclaim 6, wherein the object has a sensitive layer, and the patterningdevice generates a pattern on the object by exposing the sensitive layerwith irradiation of an energy beam.
 8. An exposure apparatus that formsa pattern on an object with irradiation of an energy beam, the apparatuscomprising: a patterning device that irradiates the object with theenergy beam; and able body drive system according to claim 1, whereby amovable body, on which the object is mounted, is driven by the movablebody drive system, for relative movement of the energy beam and theobject.
 9. A device manufacturing method, comprising: exposing an objectusing the exposure apparatus according to claim 8; and developing theexposed object.
 10. An exposure method of exposing an object with anenergy beam, the method comprising: holding the object with a movablebody; and driving the movable body by the movable body drive systemaccording to claim 1 and exposing the object with the energy beam.
 11. Amovable body drive system that drives a movable body substantially alonga predetermined plane, the system comprising: a scale which is placed,with a first direction serving as its longitudinal direction, on a firstplane that faces the movable body and is parallel to the predeterminedplane, and in which a two-dimensional grating whose periodic directionsare in the first direction and in a second direction perpendicular tothe first direction is formed; a measurement system which has aplurality of two-dimensional heads that are placed at differentpositions in the second direction on a second plane of the movable bodysubstantially parallel to the predetermined plane and have theirmeasurement directions in the first and second directions, and whichcomputes positional information of the movable body in at leastdirections of two degrees of freedom within the predetermine planeincluding the first and second directions based on an output of thetwo-dimensional head that faces the scale; and a drive system thatdrives the movable body along the predetermined plane based on thepositional information that has been computed by the measurement system.12. The movable body drive system according to claim 11, wherein thescale has a width, which three of the two-dimensional heads cansimultaneously face, in the second direction, and the measurement systemcomputes positional information of the movable body in directions ofthree degrees of freedom within the predetermined plane, based onoutputs of at least two of the two-dimensional heads that simultaneouslyface the scale.
 13. The movable body drive system according to claim 11,wherein the drive system includes a planar motor that drives the movablebody along the predetermined plane.
 14. A pattern formation apparatusthat forms a pattern on an object, the apparatus comprising: apatterning device that generates a pattern on the object; and themovable body drive system according to claim 11, whereby a movable body,on which the object is mounted, is driven by the movable body drivesystem, for pattern formation to the object.
 15. The pattern formationapparatus according to claim 14, wherein the object has a sensitivelayer, and the patterning device generates a pattern on the object byexposing the sensitive layer with irradiation of an energy beam.
 16. Anexposure apparatus that forms a pattern on an object with irradiation ofan energy beam, the apparatus comprising: a patterning device thatirradiates the object with the energy beam; and the movable body drivesystem according to claim 11, whereby a movable body, on which theobject is mounted, is driven by the movable body drive system, forrelative movement of the energy beam and the object.
 17. A devicemanufacturing method, comprising: exposing an object using the exposureapparatus according to claim 16; and developing the exposed object. 18.An exposure method of exposing an object with an energy beam, the methodcomprising: holding the object with a movable body; and driving themovable body by the movable body drive system according to claim 11 andexposing the object with the energy beam.
 19. An exposure method ofexposing an object held by a movable body that moves substantially alonga predetermined plane, with an energy beam, wherein a first scale and asecond scale are placed on a first plane that faces the movable body andis parallel to the predetermined plane, the first scale being placedwith a first direction serving as its longitudinal direction and havinga first grating formed therein whose periodic direction is in the firstdirection or in a second direction perpendicular to the first direction,and the second scale being placed with the second direction serving asits longitudinal direction, and having a second grating formed thereinwhose periodic direction is orthogonal to the periodic direction of thefirst grating, the method comprises: a measurement process of computingpositional information of the movable body in at least directions of twodegrees of freedom within the predetermine plane including the first andsecond directions, based on an output of a first head that faces thefirst scale and an output of a second head that faces the second scale,from among a first head group including a plurality of the first headsthat are placed at different positions in the second direction on asecond plane of the movable body substantially parallel to thepredetermined plane and have their measurement directions in theperiodic direction of the first grating, and a second head groupincluding a plurality of the second heads that are placed at differentpositions in the first direction on the second plane of the movable bodyand have their measurement directions in the periodic direction of thesecond grating; and a drive process of driving the movable body alongthe predetermined plane based on the positional information that hasbeen computed in the measurement process.
 20. The exposure methodaccording to claim 19, wherein the first scale has a width, which threeof the first heads can simultaneously face, in the second direction, andin the measurement process, positional information of the movable bodyin directions of three degrees of freedom within the predetermined planeis computed, based on outputs of at least two of the first heads thatsimultaneously face the first scale and an output of the second headthat faces the second scale.
 21. The exposure method according to claim19, wherein a pair of the first scales are placed at a predetermineddistance on the first plane, with the first direction serving as theirlongitudinal directions, the first head group is placed on the secondplane of movable body in an arrangement in which at least one each ofthe first heads can simultaneously face each of the pair of the firstscales when the movable body is located in a predetermined effectivearea, and in the measurement process, positional information of themovable body in directions of three degrees of freedom within thepredetermined plane is computed, based on outputs of two of the firstheads that simultaneously face the pair of the first scalesrespectively, and an output of the second head that faces the secondscale.
 22. The exposure method according to claim 19, wherein a pair ofthe second scales are placed at a predetermined distance on the firstplane, with the second direction serving as their longitudinaldirections, the second head group is placed on the second plane of themovable body in an arrangement in which at least one each of the secondheads can simultaneously face each of the pair of the second scales whenthe movable body is located in the effective area, and in themeasurement process, positional information of the movable body indirections of three degrees of freedom within the predetermined plane iscomputed, based on outputs of two of the first heads that simultaneouslyface the pair of the first scales respectively and outputs of two of thesecond heads that simultaneously face the pair of the second scalesrespectively.
 23. A device manufacturing method, comprising: exposing anobject using the exposure method according to claim 19; and developingthe exposed object.
 24. An exposure method of exposing an object held bya movable body that moves substantially along a predetermined plane,with an energy beam, wherein a scale, in which a two-dimensional gratingwhose periodic directions are in a first direction and in a seconddirection perpendicular to the first direction is formed, is placed withthe first direction serving as its longitudinal direction, on a firstplane that faces the movable body and is parallel to the predeterminedplane; the method comprises: a measurement process of computingpositional information of the movable body in at least directions of twodegrees of freedom within the predetermine plane including the first andsecond directions based on an output of a two-dimensional head thatfaces the scale, from among a plurality of the two-dimensional headsthat are placed at different positions in the second direction on asecond plane of the movable body substantially parallel to thepredetermined plane and have their measurement directions in the firstand second directions; and a drive process of driving the movable bodyalong the predetermined plane based on the positional information thathas been computed in the measurement process.
 25. The exposure methodaccording to claim 24, wherein the scale has a width, which three of thetwo-dimensional heads can simultaneously face, in the second direction,and in the measurement process, positional information of the movablebody in directions of three degrees of freedom within the predeterminedplane is computed, based on outputs of at least two of thetwo-dimensional heads that simultaneously face the scale.
 26. A devicemanufacturing method, comprising: exposing an object using the exposuremethod according to claim 24; and developing the exposed object.